This invention relates to a biocalorimeter in general and more particularly to a biocalorimeter that can operate in a space environment for making metabolic heat release measurements of laboratory animals under study by researchers who are investigating the effects of weightlessness. This requires a waste management system for the biocalorimeter.
In the quest for more knowledge about zero-gravity space and about the extent to which man may travel in space, it is contemplated that metabolic heat release measurements will be conducted with caged animals traveling in space. This will require an air ventilation system for maintaining both the life and comfort of the animal with means for removing odors from the air, but in order to make metabolic heat release measurements, the system should also include a waste removal and accumulation system.
One of the problems is preventing wetting of the calorimeter system components. Under zero-gravity conditions, droplets of urine can float in the enclosure and spread over calorimeter components. It is important to provide calorimeters that are free of not only urine but also feces.
When making metabolic heat release measurements with a direct calorimeter system, one of the terms that contributes to the metabolic sum is the evaporative heat transfer from the animal. Normally in a gravity environment, the urine voids are absorbed in some convenient way within the animal cage, such as by providing a shallow layer of mineral oil covered with a grate. Gravity carries the urine through the grate into the mineral oil. But in a zero-gravity environment, droplets of urine will normally float in the air surrounding the animal and finally be deposited on the surfaces of the calorimeter components. Such urine deposition will affect metabolic heat release measurements. This nonprototypic evaporative term distorts the metabolic heat release measurements. Therefore, it is highly desirable to remove urine as well as feces which contain moisture and can become coated with urine. In a more general sense, biological researchers would like to have clean calorimeters system free of urine and feces.